Air Oil Separator is very easy to install and simple to use. The blow-by gases leaving from the engine cylinders might contain oil from the crankcase. To lower pressure, these blow-by gases must be recirculated back into the cylinders. In essence, they serve as a filter for the air that is circulated through the system. Air Oil Separator requires very low maintenance and replacement costs. Many cars, especially those that are prone to oil build-up in blow-by gases, might benefit from this separator.